This invention relates to hot beverage containers. More particularly, the invention relates to a carafe for holding brewed coffee, the carafe including a lid, with both the carafe and the lid being designed to facilitate coffee flavor retention. The invention also relates to a beverage container in conjunction with a base member configured for modulating, varying and/or limiting the amount of heat provided to the hot beverage container.
Coffee brewing machines, or coffee makers, are well-known and widely available in a significant number of forms. In a conventional, automatic drip-type coffee maker, there is provided a water reservoir, a water-heating element, a basket or other container for containing ground coffee, typically mounted on a filter, a carafe and a carafe-heating element. In typical form, the water reservoir will be filled with the desired amount of water. The user then places ground coffee in a filter, both of which are then located in the basket. A beverage container or carafe is placed on the hot plate. The coffee machine is then switched on, and water is drained from the reservoir, heated, and conveyed to the basket. The hot water, which may have some steam mixed therein, passes through the coffee and coffee filter, acquiring the necessary flavor, and is then channeled through a small orifice in the basket so as to drip into the carafe which is situated below it. When all the water in the reservoir has passed through the system into the carafe, it remains stored therein, and the coffee within the carafe is heated and kept hot by heat from the hot plate.
A typical carafe may comprise a lid which fits around the brim of the carafe. The lid for a conventional carafe would have two apertures therein, one usually centrally located through which the coffee can pass from the basket into the carafe, and another, usually peripherally located, through which the stored coffee can be poured from the carafe into a cup or other container. These two apertures leave a significant “exposed” or open area across the brim of the carafe.
The hot plate on which the freshly brewed coffee in the carafe is mounted typically keeps the temperature of the coffee at approximately 150° F. to 185° F. As mentioned, the conventional carafe lid, if present, is designed to provide sufficient open area between the inside of the carafe and the outside thereof, in order to allow the brewed coffee to fall from the basket, into the carafe, and for pouring brewed coffee therefrom. Therefore, while this open area is intended to meet certain needs, it also constitutes a wide open path for the heated, brewed coffee within the carafe to evaporate. Thus, as long as heat is being applied from an external source (the hot plate) to the coffee within the carafe, referred to as the “keep warm mode”, the heating and evaporation of the coffee produces a continuous reduction in the volume of the original brew. Both water and aromatic compounds are continuously lost, eventually leaving behind a thick soup of bad-tasting chemicals. Eventually, usually after about 20 to 30 minutes, the coffee becomes unfit to drink. Further, if left on the hot plate for extended periods of time, the coffee will eventually lose all of its water to evaporation, leaving a thick paste burnt at the bottom of the carafe, which is very difficult to remove.
As will be noted from the above discussion, the “keep warm mode” temperature is actually sufficiently high to cook the brew. Therefore, conventional coffee makers will only retain a flavorful and desirable coffee brew for a limited amount of time, and the extended application of heat through the hot plate eventually ruins the coffee.
The prior art shows various attempts to correct this problem. For example, U.S. Pat. No. 5,699,719 (Lucas) shows a thermal carafe brewing device including a pressure control valve which prevents liquid and heat from flowing out of the carafe through the lid. U.S. Pat. No. 4,526,797 (Stone) tries to address this problem by teaching a “temperature differential” concept, but does not provide a sealed lid. U.S. Pat. No. 4,638,929 (Stone) discloses an injection-molded top assembly for open-mouth coffee pots, and comprises two injection-molded parts, and a self-sealing top assembly to achieve this.
U.S. Pat. No. 6,246,032 (Quinn) shows a fabric disc to protect the flavor of coffee or tea from excess heating, comprising heat-resistant fibers, while U.S. Pat. No. 4,715,269 (Stoner) includes a closed top decanter and warming plate, heated to a temperature only slightly above the desired temperature of the coffee.